论文部分内容阅读
以K2O为助熔剂,在较大的固液界面温度梯度条件下,应用坩埚下降法技术生长了初始Ni2+掺杂摩尔分数为0.5%的近化学计量比铌酸锂晶体。测定了晶体的吸收光谱,观测到由Ni2+离子在八面体中3A2g(F)→3T1g(P)、3A2g(F)→3T1g(F)、3A2g(F)→3T2g(F)能级的正常自旋允许跃迁所产生的381 nm,733 nm,1280 nm吸收峰和3A2g(F)→1T2g(D)和3A2g(F)→1E(D)能级的自旋禁戒跃迁产生的430 nm与840 nm吸收峰。从晶体紫外吸收边的位置初步估算其摩尔分数比x(Li+)/x(Nb5+)为0.981。根据晶体分裂场理论和吸收光谱,计算了Ni2+在该铌酸锂晶体中的晶格场分裂参量Dq=781 cm-1、Racah参量B=1096 cm-1与C=4353 cm-1。研究了在不同激发波长下晶体在可见光波段的荧光特征,观察到500~630 nm的绿色与800~850 nm的红色荧光发射带,它们归结为1T2g(D)→3A2g(F)与1T2g(D)→3T2g(F)的能级跃迁所致。
Using K2O as flux, a near stoichiometric lithium niobate crystal with initial Ni2 + doping mole fraction of 0.5% was grown by the crucible descent method under the condition of large solid-liquid interface temperature gradient. The absorption spectra of the crystals were measured and the normal order of the energy levels of 3A2g (F) → 3T1g (P), 3A2g (F) → 3T1g (F), 3A2g (F) → 3T2g (F) The spin-forbidden transitions at 381 nm, 733 nm, 1280 nm and 3A2g (F) → 1T2g (D) and 3A2g (F) → 1E (D) nm absorption peak. The molar ratio of x (Li +) / x (Nb5 +) was estimated to be 0.981 from the position of UV absorption edge. According to the theory of crystal splitting field and absorption spectrum, the lattice parameter field splitting Dq = 781 cm-1 and the Racah parameter B = 1096 cm-1 and C = 4353 cm-1 of Ni2 + were calculated. The fluorescence characteristics of the crystal in the visible region at different excitation wavelengths were studied. The green emission spectra at 500-630 nm and the red emission bands at 800-850 nm were observed. They are summarized as 1T2g (D) → 3A2g (F) and 1T2g (D) ) → 3T2g (F).